DULUTH — A long-awaited revised environmental review of a proposed copper-nickel mine in northeastern Minnesota will be released Nov. 22, the state Department of Natural Resources said Friday.

The proposed PolyMet mine would be the first copper-nickel mine in the area. The 1,800-page environmental impact statement, a detailed plan for how the mine will operate in compliance with state and federal environmental regulations, has been years in the making.

PolyMet is proposing a $600 million open-pit mine near Babbitt and a processing center at the old LTV taconite mine north of Hoyt Lakes.

The project has been substantially reworked since the original version of the statement in 2009 to meet concerns of regulatory agencies and others about long-term implications of emissions, especially potentially acidic runoff when the copper-bearing rock is exposed to water and air.

The U.S. Environmental Protection Agency rejected the original environmental impact statement in 2010 as inadequate.